The art of powering wearable electronics

-July 15, 2017

 

Texas Instruments Power management reference design for wearables5

TI has a viable, scalable power solution for wearables which can be adapted to watches, activity monitors, and other types of wearable devices. It’s reference designs like this in Reference 5 that will enable designers to add their talent and creativity to reach new levels of powering techniques in wearables. See Figure 15.


Figure 15: The block diagram of the TI wireless power solution for wearables (Image courtesy of Texas Instruments)

 

Linear Technology (now part of Analog Devices) medically wearable and scalable power solutions6

Linear Technology has an energy harvesting solution with their LTC3107 that can power a Wireless System Network and charge batteries. See Figure 16.



Figure 16: A Thermoelectric generator-powered energy harvesting design that could extend primary cell life (Image courtesy of Linear Technology, now part of Analog Devices)

There is also an LTC3331 that can convert energy from multiple energy sources to power wearables. See Figure 17.



Figure 17: The LTC3331 has a full-wave bridge rectifier for inputs from piezo (AC energy), solar (DC energy), and other energy sources like magnetics (AC energy). (Image courtesy of Linear Technology, now part of Analog Devices)

Some other ideas to spur creative activity among designers

Microphone wake up and listen for wearables

Vesper has a pretty neat solution to save power that can be used for voice control in wearables, see this article entitled Wake up and listen: Vesper quiescent-sensing MEMS device innovation

Information gathering for wearables challenges power consumption reduction

I am not so sure how long Intel will stay in this business, but they have been developing a low-power ‘Always-on’ IC on its 14 nm process that would consume 2 mW for keyword recognition. They also have their Curie Module powered by their Quark SE SoC. Intel’s Jerry Bautista, VP/General manager of the Intel New Devices Group has commented that they consider data extremely valuable, and wearables can help gather more information, especially biometrics. Wearables are edge devices that collect data and feed them to into the large flow of data being sent to cloud servers for analysis. Reducing the power consumption in these types of devices is paramount at Intel.

I fully anticipate, with excitement, the next innovative power solutions for wearable electronics that will be virtually invisible to the user. Maybe I will put my smart watch back on when that happens.

Stay tuned to my EDN and Planet Analog sites for more in-depth discussions and applications on this topic coming soon.

References

  1. Garment level power distribution for wearables using inductive power transfer, Paul Worgan and Mike Fraser, Bristol Interaction Group, IEEE 2016.
  2. A Study of Wireless Power Transfer Topologies for 3.3 kW and 6.6 kW Electric Vehicle Charging Infrastructure, Mingyu Park, Van Thuan Nguyen, Seung-Duck Yu, Seong-Woo Yim, Kijun Park, Byung Duk Min, Seung-Do Kim, and Jung Gu Cho, 2016 IEEE Transportation Electrification Conference and Expo, Asia - Pacific (ITEC) June 1 - 4, 2016
  3. Millimeter-wave Ink-jet Printed RF Energy Harvester for Next Generation Flexible Electronics, Jo Bito, Valentina Palazzi, Jimmy Hester, Ryan Bahr, Federico Alimenti, Paolo Mezzanotte, Luca Rosell, Manos M. Tentzeris, IEEE 2017.
  4. Wireless Power, Energy Harvesting, & Power Management Solutions for Sensors and the IoT presentation by Charles Greene, Ph.D., Sensors expo & conference, 2017
  5. Power Management Reference Design for a Wearable Device with Wireless Charging Using the bq51003 and bq25120, Application report SLUA748A, Texas Instruments, April 2016
  6. Medically Wearable, Scalable & Available, Tony Armstrong, Linear Technology

Also see:

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